The tlincalli (the name appears to be completely invented, not based in myth, but it looks Nahuatl to me, so I’m going to pronounce it
tlhin-ky-yee—nope! That’s a Spanish pronunciation. As reader Victor R. points out, in Nahuatl, each l is pronounced as a separate l, so it’s tlhin-KAHL-lee) is a centaur-like monstrosity with a humanoid torso topping a scorpioid body. Based on the illustration in Volo’s Guide to Monsters, its face is pretty awful as well, although details are hard to make out.
With very high Strength and Constitution and merely above-average Dexterity, tlincallis are brutes, unafraid of direct melee confrontation. Their Intelligence is below humanoid average, though not animal-level, while their Wisdom is above average, allowing them to pick out promising prey—the old, the young, the weak, the isolated and the oblivious—as well as to realize when a particularly dangerous opponent needs to be taken out.
The combination of proficiency in Perception and Stealth is indicative of an ambush attacker; proficiency in Survival adds the ability to track, which is consistent with the flavor text’s characterization of them as nomadic hunters. Tlincallis hot on the trail of desirable prey will pursue it aggressively until either they bag it or it fights back forcefully enough to deter them.