Combine the first 7 ingredients in small bowl. Add half of the mixture in a zip-lock bag and reserve the remaining mixture. Add the chicken to the bag and let sit in the fridge for 2 hours, or longer. The more the chicken sits, the more the flavors will mix together and taste even better!
Preheat grill or a large skillet on medium-high heat and add a tablespoon or so of fat.
Remove chicken from the baggy. Add a bit of sea salt on the chicken, and place the chicken on the grill or in the skillet to cook. The chicken will need cook for about 8-10 minutes on both sides or until done. If you are cooking in a skillet and want the chicken to cook a bit quicker, add a bit of water and cover to let the steaming begin.
Serve the chicken on top of any sort of veggies you like and top with reserved mustard mixture. I used a mixture of zucchini noodles (zucchini sliced thin with a mandoline) and some broccoli, which i sautéed up with the chicken when it was almost done cooking!