I would guess that by "fillet", you are talking about bnls/skls breast? Since you're dealing with little to no fat, I would try to get some schmaltz to saute with. This will leave you with some pretty tasty pan dripping that you can turn into a sauce. Once you pull your chicken to rest, put your skillet back over medium heat and add a Tbsp or so of flour. Wisk to mix in the flour and cook to remove the raw flour taste. While wisking, add some white wine and dijon mustard. While continuing to wisk, add some chicken stock and bring to a boil. The sauce will not reach its thickest until brought to a boil. Add more stock if too thick. S&P to taste.
For sides, I like sprouts, broccoli, carrots and green beans. Basically, a single green vegi or vegi combo.