In a small bowl, whisk together soy sauce, water, honey, brown sugar, and garlic. If honey won't dissolve, microwave the marinade for 20 seconds and whisk again.
Set aside 3/4 cup of the marinade for basting while cooking (can be stored in the refrigerator in an airtight container until ready to use). Pour remaining marinade in the Ziploc bag (quart sized) with the chicken. Squeeze out excess air and seal bag.
Let chicken marinate in the refrigerator for at least 30 minutes. For best results, marinate for 4 hours or ideally overnight.
When ready to cook, prepare grill per unit instructions. Remove chicken from marinade bag and thread on skewers. Discard the bag and marinade that chicken rested in.
Place chicken on grill and cook until done and no longer pink, roughly 3-4 minutes per side. When turning kabobs, use the reserved 3/4 cup of marinade to baste chicken.
For the Sriracha Cream Sauce
While the chicken cooks, add mayonnaise, sririacha, and sweetened condensed milk in a small mixing bowl, then whisk together until creamy. Taste test and add more sriracha if desired.
Putting it All Together
Serve chicken kabobs immediately, drizzled with sriracha cream sauce and sprinkled with chopped chives (optional).