In large zip-top bag (or in large container with lid), add chicken, olive oil, garlic, vinegar, bouillon, Sazón, Adobo, mustard and sugar. Seal bag and massage to coat chicken in marinade. Transfer chicken to refrigerator. Chill at least 30 minutes, or up to 24 hours.
Bring chicken to room temperature 30 minutes before cooking. Meanwhile heat butter in medium saucepan over medium heat until melted. Stir in hot sauce, Sazón and brown sugar; bring hot sauce to boil. Reduce heat to low. Simmer, stirring occasionally, until sauce thickens, about 5 minutes. Remove pot from heat; keep warm.
Heat 2” oil in large, heavy saucepan over medium-high heat until temperature registers 350°F on deep-fry thermometer. (Or, heat deep fryer to 350°F.) Toss chicken in flour, patting off excess. Fry chicken in batches until golden brown and cooked through, about 4 minutes per batch. Using slotted metal spoon, transfer chicken to paper towel-lined plate to drain.
Transfer fried chicken to saucepan with hot sauce. Using spoon, stir chicken to coat in sauce. Transfer chicken to serving platter. Serve warm.