I looked...I have
NX Advanced FEM
NX Mach 3 Ind Design
NX Mach 2 Prod Design
I looked in all of them and see nothing for it. Does this mean I need to purchase another bundle? Do you know what bundle I need?
Select the NX Advanced FEM bundle beforehand.
I'm not a CAE expert, but I think your Advanced FEM license doesn't allow using Design Simulation.
In the applications tab, you could try clicking on Advanced or Pre/Post (depending on the version of NX being used, see image below).
Design and Advanced Sim are two different license bundles each requiring their own licensing.