Will Chevy wheels fit a 1994 Nissan d21?

If its the 6 lug, yes and no. I just put a set of 16" chevy 1500 6 lug rims on my 89 d21.

I first fit the rims on and noticed the center hole on the rims were too small to fit over the center of the hubs on the d21. I was going to bore the center of the rim to fit, but ran into another problem. If I did that it seemed too close to the lug holes ( chevy lug holes are bigger, a 4" hole in the center seemed too close). I ended up grinding my center hubs down so they fit the chevy rim center.

So yes it can be done, but it will take some work. If you do trim the center hubs be very careful and even, don't throw the weight balance off. If you bore out the rim, for the most part, any unevenness will be dissolved when you have the tires balanced.