^ The process is NOT random, as @Indigoraccoon4 suggests; that implies applications being tacked up on a wall, and darts being thrown at them to determine who gets accepted or not. It’s a bit more involved than that.
Notwithstanding, a look at the Common Data Set is going to inform you as to where most admitted applicants fall in terms of GPA and standardized test scores. There are always statistical outliers to those ranges; and the university AOs have their reasons for selecting those persons who fall outside those ranges.
The OP is asking about “chances,” or probabilities, or likelihood of admission. The ultimate decision about admission is something that is different than the “chance” of admission. The most recent Super Bowl is an example: at the end of the 3rd quarter, the chances of the New England Patriots winning were abysmally low, but they still won the game. Does that result change the fact that their chances were low at a critical point in the game? No.
Same thing here. The fact that your “chances” may be good or bad is not an absolute predictor of the ultimate outcome; but it may inform your decisions on how a person addresses the application process at UNC-CH and elsewhere, and the expectations you have about your success (or not) in getting accepted.