Pat the chicken pieces dry with paper towels (dry chicken browns; wet chicken steams). Season with salt, pepper, garlic powder, and paprika.
Heat the olive oil in a large skillet over medium-high heat until shimmering.
Add the chicken in a single layer — don't crowd the pan (work in two batches if needed). Sear 2 to 3 minutes per side until golden and cooked through.
Push the chicken to the edges of the pan. Drop in the butter and let it melt, then add the garlic and cook 30 seconds until fragrant.
Squeeze in the lemon juice, toss everything together, and shower with parsley. Serve immediately.