Combine first seven ingredients in a medium bowl except for the onion. Place pork chops into a gallon size bag and set into a casserole dish to prevent spills. Place onion in bag on top of pork chops and pour in the marinade. Let marinate in the fridge overnight, turning a couple of times to ensure all sides get evenly marinated.
Remove pork chops from marinade and allow to come up to room temp while the grill heats up on high. Meanwhile, strain the onions out of the marinade, but save the marinade. In a small pot, bring it to a boil over medium high heat and boil for 15-20 minutes until reduced to a thick glaze. This step can even be done on indirect heat on your grill.
Toss the onions you saved into a saute pan with a pat of butter and caramelize on medium low heat. I recommend using the side burner on your grill if you've got one. If not, again, toss it on indirect heat on the grill.
Once the grill is hot, use a barbecue fork to place each chop on the hottest spot of your grill. Cook for 2-3 minutes per side. Brush with glaze after each flip. Move to indirect heat and continue to cook for 7-10 more minutes while brushing with beer glaze occasionally.