Bring a large saucepan of water to the boil (preparation to cook the pasta)
Dice the chicken breast, slice the onion and crush the garlic cloves, season with salt and pepper. Add the oil to a frying pan and brown the chicken, onion and garlic for 6-8 minutes.
Add the carbonara sauce to the frying pan, stir and simmer the chicken uncovered for 10-15 minutes
Add the pasta to the saucepan of boiling water. Cover and simmer for 8 minutes, add the frozen mixed vegetables, cover and continue to simmer until the vegetables are cooked. Drain the water once cooked
Combine the cooked chicken with the pasta and vegetables. Toss to coat in the carbonara sauce. Taste and season with salt and pepper