Heat olive oil over medium heat in a 12" cast iron skillet or paella pan. Add chicken and chorizo (if using), sauteing until cooked through. Stir in garlic and paprika and cook for 1 minute.
Add tomato sauce, broccoli and haricots vert. Saute for 2-3 minutes until bright green but still crunchy.
Add broths and/or wine (if using). Turn up heat to medium high and bring to a boil. Stir in rice and clams (if using) cook for 10 minutes, adjusting heat slightly if rice mixture is about to boil over.
Lower heat to medium-low. Add saffron, mussels and shrimp and cook for another 6-8 minutes until mussels are opened, shrimp is pink and opaque, and most of the liquid has been absorbed into the rice.
Remove from heat and cover with clean, dry paper towels for 5-10 minutes (this process allows the rice at the bottom of the pan to get crispy).