I was planning some possible encounters on Jakku and the books haven't been updated for the sequel trilogy. I wanted to see if anyone else had ideas how they would stat the monster.

Nightwatcher Worm. A few things are clear from the wookieepedia article

Wookieepedia says they get to be 20 meters in length, which is 13 to 14 squares for a worm type creature (longer than they are wide), so it seems like it'll be easily colossal unless you're fighting a juvenile.

They seem to have both tremorsense and an eyestalk about the size of a medium creature's head to poke out of the sand. They're nocturnal scavengers, so their eyestalks surely have darkvision.

Must have a burrow speed faster than a running human, so they likely have a normal move of 8sq, perhaps?

They have a ranged spittle attack, though it doesn't seem to do damage. Maybe the spittle is like a thrown weapon against Reflex Defense, if it beats Fortitude also, it blinds for 1 round (as you clear your eyes).

They probably focus on grappling with their mouths, trying to snatch prey suddenly in an ambush.