Wash and dry produce. 

Halve, peel, and slice onion into ½-inch-thick wedges. Quarter lime. Gently crush peanuts in their bag. 

Open package of chicken and drain off any excess liquid. Heat a drizzle of oil in a large pan (use a large pot for 4 servings) over medium-high heat. Add chicken and onion; season with salt and pepper. Cook, stirring occasionally, until browned, 2-3 minutes (the chicken will finish cooking in the next step).

Break noodles in half and add to pan with chicken mixture.

Increase heat to high; stir in tamarind sauce and 2 cups water (3 cups for 4 servings). Cook, stirring constantly (separating noodles as you stir), until noodles are tender and sauce has thickened, 6-7 minutes.

When noodles have 1 minute remaining, add coleslaw mix and juice from one lime wedge (two wedges for 4 servings) to pan. Cook, stirring, until veggies are just softened, 1-2 minutes. (If mixture seems dry, add a splash of water.) Taste and season with salt and pepper if desired.

Divide stir-fry between shallow bowls; squeeze one lime wedge (two wedges for 4) over bowls. Sprinkle peanuts over stir-fry. Serve with Sriracha and remaining lime wedges on the side.