Prepare your veggies. Slice the onions, mince the garlic, coarsely chop the herbs. Clean and trim the stems of the collard greens and Swiss Chard. Coarsely chop or tear into 2-3 inch pieces. Zest and juice the lemon. Set all of the prepared ingredients aside until ready to use. This can all be done several hours ahead of time.
Preheat oven to 425 ℉. Blend 1/4 cup olive oil with the garlic, salt, and coriander. Rub this mixture on top and bottom of each chicken thigh.
Heat a little of the olive oil in a large oven-proof skillet or Dutch oven. Cook over medium high heat until thighs are nicely browned. Turn thighs over and continue cooking for another 1-2 minutes. The second side does not have to be as browned. Remove chicken to a plate.
Heat a little more oil and cook the onions until translucent and just beginning to brown. Add chopped olives, cilantro, parsley, and lemon zest and continue cooking for another 2-3 minutes over medium heat, stirring occasionally.
Reduce heat to medium-low, and slowly add the chopped greens a handful at a time, until all of the greens fit into the pan, tossing them with the onions and olives in the bottom of the pan as you go. Don’t over cook the greens, just cook them enough to fit them all into the pan. They should just be beginning to wilt. Gently toss greens, onions, and olives together.
Nestle chicken thighs back into the pan among the greens. Pour chicken broth and 2 tsp. lemon juice over the top and bake for about 25 minutes, or until chicken is cooked through and tender.
To serve, spoon the greens over a bed of the polenta and place two chicken thighs on top. Serve with a lemon wedge on the side.