The Incherrito in Bugsnax can be found in the Sizzling Sands. You can find them crawling under the sand during the day, or down in the ruins at any time. Catching them is actually quite simple, if you read up on them in the Bugpedia.
Scan him so you get his Bugpedia entry, and you will see he loves cheese sauce and hot sauce. They all cannot dig through solid rock, so if you can lead them the rocks they will have no choice but to crawl out of the dirt.
Set up your Snak Trap on a nearby rock, the place some cheese or hot sauce under it. Leave a trail of the tasty goop to the Incherrito’s trail and he will follow it and eventually crawl out on the rock.
This will leave him exposed, and you can activate the trap to get him. You will need to catch one of these guys later in the game of Wambus, so if you do catch one early, leave it in your inventory because you will need it later on.