I discuss in my answer here, AtharvaVeda states Universe as like projection in space-time:
पूर्ण कुम्भोदिः काल आहितस्तं वै पश्यामो बहुदा नु सन्तः । [AtharvaVeda 19.53.3]
A full pot has been placed in Time and it is that which we see manifoldly.
Similarly as I discuss here, RigVeda states the present creation is similar like the past creation:
The Ordainer created the sun and moon like those of previous cycles. He formed in order Heaven and Earth, the regions of the air, and light.
And RigVeda also states it is Indras (Gods) form seen as many due to Maya, which I discuss here:
रूपं-रूपं परतिरूपो बभूव तदस्य रूपं परतिचक्षणाय |
इन्द्रो मायाभिः पुरुरूप ईयते युक्ता हयस्य हरयःशता दश || (RigVeda 6.47.18)
In every figure he hath been the mode: this is his only form for us to look on. Indra assumes many form by his Maya, for his Bay Steeds are yoked, ten times a hundred.
Combining all these three statements at the same time we can get strong hint of Universe being like a simulation type, although this may not exclusively prove that Universe is simulation.
In the Yoga-Vasistha there is a story which very much resembles the above description given in the story. In this story Indra enters inside atom and he forms his Kingdom inside that atom through his imagination. But that imagination formed world begins to work like real world and other Indras (his sons) also begin to rule in that place. Book VI chapter 13 of Yoga-Vasistha contains this story and is as:
At one time the great Indra, the lord of the gods, lived in that fruit, just like a big mosquito lives in an empty pot as the great leader of its company of small gnats. But this great lord was weakened in his strength and valor by his study and his teacher’s lectures on spiritualism, which made him a spiritually minded person and a seer in all past and future matters. It happened once upon a time, when the valiant god Narayana and his heavenly host had been resting and their leader Indra was weakened in his arms, that the demon asuras rose in open rebellion against the gods. Then Indra rose with his flashing arms and fire and fought for a long time with the strong asuras. At last Indra was defeated by superior strength and fled from the field. He ran in all ten directions, pursued by the enemy wherever he fled. He could find no place to rest, just as a sinner has no resting place in the next world. Then as the enemy lost sight of him for a moment, he made use of that opportunity. He compressed the thought of his big body in his mind and became a minute form on the outside. Then through his consciousness of his personal minuteness, he entered the womb of an atom which was glittering amidst the expanse of solar rays, like a bee entering a lotus bud. He immediately rested in that state and his hope of final bliss in the next. He utterly forgot the warfare and attained the ultimate bliss of nirvana. In that lotus and instantly in his imagination, he conceived his royal palace. He sat in lotus posture as if resting on his own bed. Then Indra, seated in that mansion, saw an imaginary city containing a grand building in the middle, its walls studded with gems, pearls and coral. From within the city, Indra saw a large country all around containing many hills and villages, pasture grounds for cattle, forests and human dwellings. Then Indra felt a desire to enjoy that country he had formed in his imagination, with all its lands and hills and seas. Afterwards Indra conceived a desire to possess the three worlds, together with all the earth and ocean, sky and infernal regions, the heavens, planetary spheres above and mountain ranges below. Thus did Indra remain there as lord of the gods in possession of all abundance for his enjoyments. Afterwards, a son was born to him named Kunda, of great strength and valor. Then at the end of his lifetime, this Indra of unblemished reputation left his mortal body and became extinct in nirvana, like a lamp extinguished for lack of oil. Kunda reigned over the three worlds. Then, having given birth to a boy, he departed to his ultimate state of bliss after the end of his life term. That son also ruled in his time, then departed at the end of his lifetime to the holy state of supreme bliss. He also left a son after him. In this manner a thousand generations of grandsons of the first Indra have reigned and passed away in their time. There is still a prince named Ansaka reigning over the land of the lord of the gods. Thus generations of the lord of immortals still hold sovereignty over the imaginary world of Indra in that sacred particle of sunbeam in empty air. That atomic particle is continually decaying and wasting in this long course of time.
This story clearly gives account of very advanced simulation world formed by Indra.
As a sidenote, Adi Shankara in his Dakshinamurty Stotram also states that Universe is like a city seen within mirror and happening inside one's self:
The Entire World is Like a City Seen within a Mirror, the Seeing happening within One's Own Being, It is a Witnessing happening within the Atman, (the Witnessing) of the Externally Projected World; Projected by the Power of Maya; As if a Dream in Sleep, One Experiences this Directly (this Play of Maya) during Spiritual Awakening within the Non-Dual Expanse of One's Own Atman,