Combine the chicken tenders, avocado oil, and blackened seasoning in a mixing bowl or zip-top bag; toss to coat and set aside to marinate while you prepare the other components.
In a small bowl, whisk together mayonnaise, brown sugar, hot sauce, Dijon mustard, Worcestershire sauce, and lemon juice until smooth; set the sauce aside.
In another small bowl, whisk the melted butter with minced garlic and chopped parsley to make the butter topping for the buns.
Line a baking sheet with foil and slice the slider rolls in half horizontally; place the bottoms on the sheet and set the tops (cut-side up) aside on the sheet for broiling.
Heat a large skillet over medium-high heat. Add the marinated chicken and cook 3–4 minutes per side, until well-charred and cooked through (internal temperature 165°F / 74°C).
While the chicken cooks, brush the butter mixture over the cut top halves of the buns and broil on high for about 2 minutes until lightly golden and crisp—watch carefully to avoid burning.
Arrange cooked chicken evenly on the bottom halves of the rolls. Top with cheese slices (use about 6 slices across the sliders as desired), shredded lettuce, sliced red onion, and dill pickle slices.
Drizzle or spread the prepared sauce over the toppings, place the toasted top buns on each slider, then serve immediately.