In an 18- to 20-inch paella pan, large Dutch oven or deep skillet, heat 2 tbsp. oil over medium-high. Season the chicken with salt and pepper. Cook until browned on one side, 5 to 7 minutes; turn. Scatter the chorizo around the chicken. Cook, stirring the chorizo occasionally, until the chicken is cooked through and the chorizo is browned, about 5 minutes; transfer to a bowl. (If using a Dutch oven, transfer the chicken to a bowl and continue cooking the chorizo until browned, 2 to 3 minutes more; add to the bowl.)
Reduce the heat to medium; add 1 tbsp. oil, the onion, bell pepper, garlic, bay leaves and paprika. Cook, stirring often, until the vegetables soften, about 5 minutes. Stir in the rice. Add 5 cups stock; bring to a boil. Reduce the heat to medium; simmer, stirring occasionally and adding more stock by the cup if too dry, until the rice is almost al dente, 13 to 15 minutes.
Meanwhile, slice the chicken into thin strips.
Increase the heat to high. Stir the chicken and chorizo into the rice; season. Scatter with the peas; cook, without stirring, until the rice is al dente and forms a crust on the bottom of the pan, about 5 minutes. Top with the parsley.
