Combine garlic and dry ingredients in a medium bowl. Slice chicken into small chunks or strips and coat all sides with seasoning. Heat olive oil in frying pan. Cook chicken on high for five mins, stirring frequently.
Meanwhile, chop veggies into chunks or strips. Add veggies to pan of chicken, stir and cover. Cook covered for 3-4 mins, stirring occasionally, until onion is translucent.
Uncover, add tomato paste and lemon juice, and cook uncovered for another 3 mins. Remove pan from heat. Scoop fajita mix onto tortillas and decorate with your fave toppings.