This recipe KILLs every time I make it. It's just unbelievably good and so easy and a crazy bright but balanced array of flavors. The creamy grits would be good any time. The snag is the Hatch green chile powder. You can substitute another mild chile powder, and I have even made it with jalapeno powder (reduce! by a lot!)

http://www.foodandwine.com/recipes/green-chile-chicken-thighs-with-arugula-salad

I know this is too late for your party but this might help someone else with the same pickle.
I am an Ina Garten fan. If you want a dish that is foolproof (I think the woman tests each one 15 times before publishing it) she has a recipe for a beef dish that she uses filet mignons, browns them separately and adds them at the end. I suppose you could do the same thing with beef and chicken pieces. Add the cooked chicken to half the sauce and the beef to the other half. Everyone is happy.
Copy and paste to your browser..............
http://www.foodnetwork.com/recipes/ina-garten/fillet-of-beef-bourguignonne-recipe/index.html

Its seems that if your prepared to cook Boeuf Bourguignon and suddenly you have to change to a chicken recipe the obvious choice to me would be Coque Au Vin. Good luck with your evening!

Another idea I would add to the amazingly delicious Braised Moroccan Chicken if you don't have any preserved lemons: When I made this dish just this past week, I thinly sliced the lemons, sprinkled them with salt and just a little olive oil and roasted them in a 400F oven for about 15 minutes, until they were very lightly browned. Then I chopped them all up and added them to the chicken dish.

Try this Aromatic Braised Chicken with Fried Onions recipe
http://www.epicurious.com/recipes/food/views/Aromatic-Braised-Chicken-with-Fried-Onions-242308

I now bang my head into this wall all the time as "lead cook" for community meals. Because there are factions even within the non-meatatarian crowd. While I like to sneak anchovies into everything the hezbollah crowd would be all over me, as if shot Bambi had I hid them in stuff and they found out about it. But then I have Jewish friends who will eat pork if it tastes good. I have to confront this tomorrow by the way.

That Braised Moroccan Chicken Amanda suggested is a real winner. If you can't get preserved lemons before tomorrow night, you can substitute regular fresh lemons.

If you loved Julia's Boeuf Bourguignon, I think you'll be equally pleased with her recipe for Coq au Vin.

I forgot to add she has a blog called Lizthechef. http://bit.ly/bzD8JA

When people say they are "vegetarian" but will eat chicken or fish it usually means that they just don't prefer red meat. Liz the Chef has a recipe on food52 called Risotta con Gamberi (shrimp) that is very elegant and perfect for a special occasion.

Although the ingredient list is long(ish) this recipe for Braised Moroccan Chicken, which won one of our recipe contests, is very easy and straightforward to make -- and people love it. http://bit.ly/5M4eyI