Try finding blitz plays you like and tweaking them in the following ways.
1.Experiment w\ line pinching or crashing.( I like to pinch and crash in or out.)
2.Move LB's or DB's behind DT and DE's. (right behind and to the left or right of them. This is what creates that ultra quick, unblocked blitzer.)
3.REBLITZ. This means hot routing players already set to blitz, creating a bee line straight through the gaps to the QB.(Try with LB"S and D-lineman. The combo of them shooting in the same direction creates the numbers mismatches with O-line.)
4.Take user control. Find a safety or extra DB to be the last line of defense. Occaisonally if you want to blitz w\user controlled player, you can really get goodheat. It depends on the score and how aggresive you can afford to be.
5.Use sparingly. Good players can counter abused nano schemes. Save em for the times you really need a stop. All in all, nanos are good for pressure and run stuffing. Take the practice field with a friend so you have time to move players around and set up blitzes. Practice against CPU is tough because they hike so fast.
Good luck.