Need a part identification, I do not have a manual

What is the name of the part that is downstream of the mass air flow sensor for the 1996 Nissan Maxima?

Aside from something in the semi-rigid intake air plumbing, that would be the throttle body. It should have a throttle cable attached to it, unless it’s a TBW system (throttle by wire). This assumes that downstream means “toward the engine” as you view it.

Please tell us why you ask. I have fearful visions of you wanting to order one.

I don’t think your description is very thorough. Could you post a picture?

This part is square/rectangular in shape viewed as a cross section to air flow, but it is triangular in shape looking down from the hood toward the ground. It has several air hoses attached to it. One is ~2inches in diameter at the bottom. The other 2 are ~3/4 inch in diameter at the top of the part. Seems this part mixes intake air and maybe heats the air some before it goes into engine?
Anyway, 2 plastic tabs are broken off of the male inlet into part that attaches to the mass air flow sensor. This has caused an air leak, that was temporarily fixed with duct tape, but it is not working well. I need to order a new/used part that is not broken.

A salvage yard could be your best, and cheapest, source for this part. They have drawings, on cd-rom, for every part on the car. Just tell the people what you told us. The dealer might have the part for mega-bucks.

That’s the EGR/PCV intake plenum.

It’s in this component where the EGR/PCV gasses are introduced into the intake air.