Preheat the oven to 375°F.
Place the cod on one sheet pan.
Quarter the potatoes, halve the cocktail tomatoes, and trim the green beans (if necessary). Place the tomatoes on the sheet pan with the cod and place the potatoes and green beans on a separate sheet pan.
Drizzle the olive oil over both pans. Sprinkle the basil over the pan with the cod and tomatoes. Sprinkle salt, pepper, and garlic over both pans. Lightly press the pistachios on top of the cod.
Place both pans in the oven and cook for 20 minutes.
Remove the pan with the cod and let sit. Continue cooking the pan with the potatoes for 5 additional minutes.
Remove from oven, plate, and eat!