Hosw can I adjust this recipe for my 3 qt. mini instant pot? I have a 6" pan.

So that would be tough unless you had a trivet that was short enough that it would still allow the 6 inch pan to fit inside your 3 quart pot. Other than that, it should work just fine with respect to timing etc. Be sure to not overfill the pan and ensure that the pan isn’t sitting flush on the bottom of the inner liner of the instant pot.