Sim instructor requirements are found in 142.47. (If you're going to be an instructor you really ought to be able to dig through the regs.) The only exception is if you are teaching an ATP-CTP. Then you need an ATP with 2 years air carrier experience and if you are going to instruct in the sim the appropriate type rating.
The training center Training Specifications may have a higher qualification than the reg or the TC may have a policy to only hire instructors with certain ratings or experience. You would have to ask them.