In a large mixing bowl, combine the sliced chicken breast with the buffalo hot sauce, olive oil, garlic powder, smoked paprika, and a generous pinch of salt and black pepper.
Toss well until every piece is evenly coated. Let it sit for at least 10 minutes at room temperature or cover and refrigerate for up to 1 hour if you have the time. The longer it marinates, the more flavour penetrates the chicken.
Heat a large skillet or griddle pan over medium-high heat. You want the pan properly hot before the chicken goes in this is what creates the slightly charred edges.
Add the chicken in a single layer. Do not crowd the pan; cook in two batches if needed. Let it cook undisturbed for 3–4 minutes, then flip and cook for a further 3–4 minutes, until cooked through with no pink remaining and the edges have some colour.
Remove from the heat and allow to rest for 2–3 minutes before slicing. This keeps the chicken juicy.
Place each tortilla directly over a gas flame for about 20–30 seconds per side until it has a few light char spots and is pliable. Alternatively, heat in a dry skillet for about 1 minute per side.
Keep them wrapped in a clean tea towel to stay warm and soft while you assemble.
Lay each warmed tortilla flat. Spread 1 tablespoon of ranch dressing down the centre, leaving a border on all sides.
Layer with cos lettuce, avocado slices, cherry tomatoes, and shredded cheese. Top with the sliced buffalo chicken and add an extra drizzle of buffalo sauce if you like it bold.
Fold in the left and right sides of the tortilla. Starting from the bottom, roll up firmly, tucking as you go.
Slice diagonally and serve immediately. For packed lunches, wrap tightly in parchment paper they hold together well for several hours.