Make the sauce: In medium sauce pan, heat and add oil. Then add garlic and shallots, cook until translucent or slightly crisp, but do not burn these aromatics. Add fish sauce, brown sugar, vinegar, ketchup and hot sauce. Stir ingredients to combine well.
In large pot or frying pan, fill oil to about 1 inch high. Heat oil to about 350°F.
Fry chicken in batches to not overcrowd the pan, carefully place chicken into hot oil and fry on both sides till crispy and cooked, ten to fifteen minutes on each side. Do not cook on too high of heat because the chicken will finish cooking on the outside and not be cooked completely inside.
Add garlic chili sauce to large bowl and toss with fried chicken to coat well. Serve hot.