Oh, I think I see what you mean. No matter how many or how detailed the simulations you run, if your purpose is to learn something from watching them, then ultimately you are limited by your own ability to observe and process what you see.

Whoever is simulating you only has to run the simulations that you launch to the level of fidelity such that you can't tell if they've taken shortcuts. The deeper the nested simulation people are, the harder it is for you to pay attention to them all, and the coarser their simulations can be.

If you are running simulations to answer psychological questions, that should work. And if you are running simulations to answer physics questions ... why would you fill them with conscious people ?

Of course, if I were specifically trying to crash the simulation that I was in, I might come up with some physical laws that would eat up a lot of processing power to calculate for even one person's local space, but between the limitations of computing as they exist in the base simulation, the difficulty in confirming that these laws have been properly executed in all of their fully-complex glory

I was going to say that if you want to be a pain you could launch some NP hard problems that you can manually verify solutions to with a pencil and paper ... except your simulators control your random-number generators.