Preheat the oven to 400°F (204°C).
Place the Doritos in a zip-top bag, seal it, and crush them to fine crumbs using a rolling pin (or pulse in a food processor).
In a small bowl, whisk together the mayonnaise, sour cream, minced garlic, ground black pepper, and shredded Parmesan until smooth and combined.
Pat the chicken breasts dry with paper towels and season both sides with the sea salt.
Set up a dredging station: the mayo mixture in one bowl and the crushed Doritos in another. Dip each chicken breast into the mayo mixture, coating all sides, then press into the Dorito crumbs until fully coated.
Place the coated chicken breasts in an oven-safe baking dish in a single layer. For extra crispiness, place them on a wire rack set inside the dish (optional).
Bake uncovered for about 40 minutes, or until the chicken reaches an internal temperature of 165°F (74°C) and the coating is golden and crisp.
Remove from the oven and let rest briefly before serving.