To make the marinade / glaze, combine the oil, soy sauce, fish sauce, brown sugar, garlic, ginger, lemongrass, and salt. (Note: if you prefer to skip grating the garlic, ginger, and lemongrass, you can also just combine all of the ingredients in a blender or use a hand blender to blend until smooth.)
Divide the marinade in half, reserving one half to use as a glaze at the end of cooking.
In a small baking dish, combine the chicken with half of the marinade, turning to fully coat the chicken on all sides. Marinate the chicken, refrigerated, for 24 hours. (Note: You will get the most flavor if marinated for 24 hours, but even 4 to 5 hours will build flavor if that’s all the time you have.)
When you’re ready to cook, preheat the grill to medium-high heat and oil the grates.
To make the glaze, whisk the reserved half of the mariade with honey.
Grill the chicken on both sides until golden on the outside and no longer pink in the center, 5 to 7 minutes per side. (Use an instant read thermometer to check the internal temperature. The chicken is done when it registers 165°F.)
In the last few minutes of cooking, brush the chicken liberally on all sides with the glaze.
Let the chicken rest for 5 minutes before serving.