Combine coriander, fennel seeds, brown sugar, paprika, garlic powder, onion powder, and mustard seed in a small bowl until the spice mixture is well combined.

Place brisket in a glass baking dish and rub spice mixture all over the meat. Cover with plastic wrap and place in the refrigerator for 2 to 3 days.

Soak wood chips in water for at least 1 hour.

Preheat a smoker to 240°F (116°C) according to manufacturer's instructions. Maintain temperature for 15 to 20 minutes.

Drain wood chips and place on coals. Place a water pan on the smoker and add water to the depth of the fill line. Unwrap brisket and place on the lower cooking grate; cover with the smoker lid.

Cook in the preheated smoker for 2 hours. Pull brisket from the smoker and wrap tightly in foil. Return to the smoker until an instant-read thermometer inserted into the thickest part of brisket reads at least 190°F to 200°F (88°C to 93°C), about 3 hours.