I needed an easy way to mount my Gen7 electronics on my Prusa printer build. I didn't want to use standoffs and bolts because I would like to be able to remove and replace the electronics easily. So I did up some clips on sketchup and here is what I came up with. It clicks in solidly and there seems to be no tendency to slide side to side even though I didn't use any clips on the sides.

Print 2 of the clip1, 2 of clip2 and 1 of the clip3.

clip1 is for the bottom. The PCB slides into clip1 then rotates back to rest against clip2 and clip3 snaps over the top of the board to hold it down.