Heat 2 tablespoons of olive oil in a large skillet over medium-high heat until shimmering.
Add the sliced chicken in a single layer and let it brown without moving for 1 to 2 minutes, then stir and continue cooking until no pink remains, about 5 to 7 minutes total.
Push the chicken to the side of the skillet or remove briefly. Add the minced garlic and the mixed vegetables to the pan. Sprinkle oregano, paprika, salt, and pepper over the vegetables.
Stir-fry, tossing frequently, until the vegetables are bright and tender-crisp, about 5 to 7 minutes.
Return the chicken to the pan and squeeze the juice of one lemon over the mixture; stir well so the lemon coats everything evenly.
Turn off the heat, sprinkle with chopped fresh parsley, and serve immediately.
Notes
This stir fry is versatile; serve over rice, cauliflower rice, or warm pita bread. Great for meal prep and leftovers.