Set up your grill for even medium-high heat. If using a charcoal grill, distribute the coals evenly. If using a gas grill, heat both sides evenly.
To a large mixing bowl, add the melted butter, seafood seasoning and chili flakes. Mix to combine. Add the potatoes and corn and toss to coat. Season with salt and pepper. Transfer to a steamer basket.
To the bottom of a steam pot, add the chicken stock, beer, garlic, onions and a pinch of salt and black pepper and cover with a lid. Place the steamer basket onto the steam pot and place on the grill. Steam until the corn and potatoes are cooked three-quarters of the way through, 15 to 20 minutes.
Meanwhile, sear the chorizo on all sides until the skin is charred, 2 to 3 minutes per side, then add to the steamer basket. Cover with the lid and cook for 5 more minutes. Add the clams, cover and cook until the clams have steamed open, 5 to 8 minutes.
Pour the clams, chorizo, potatoes and corn onto a paper-lined table. Garnish with lemon wedges. Strain the broth into a smaller pot. Whisk in the cubed butter and hot sauce. Pour into mugs and serve alongside the clam bake.