In a small bowl, whisk together the smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne pepper, sea salt, and black pepper to create the blackening seasoning.
Pat the chicken tenders thoroughly dry with paper towels, then toss them in the spice mixture until every surface is generously coated.
Heat the avocado oil in a large cast-iron skillet over medium-high heat until it begins to shimmer.
Carefully place the chicken tenders in the hot skillet and sear for 3 to 4 minutes per side, allowing a dark, flavorful crust to form, until the internal temperature reaches 165°F.
While the chicken is searing, place the broccoli florets in a steamer basket over boiling water and steam for about 5 minutes until they are bright green and tender-crisp.
Prepare the garlic aioli by combining the avocado oil mayonnaise, minced garlic, and lemon juice in a small bowl, stirring until smooth.
Plate the blackened chicken tenders alongside the steamed broccoli and serve with the garlic aioli on the side for dipping.