Splitgate

I don’t have this achievement yet, but the way I’m making progress (68% so far) is by spawning, throwing a portal at a wall (rb/lb), and then finding a spot with a high vantage point/enemy spawn and throwing the other portal (lb/rb). It took me a while to figure out you have to press lb or rb to differentiate the portals but if you make the opposite portal have a decent sized line of sight, you should get a few kills per game.

Personally my favorite/easiest map to do it on is Stadium, since you can sit up top and shoot a portal across the map and kill anybody that comes up if you shoot your other portal on your side. It’ll work for all maps tho.