Combine 2 cups spinach, 1/2 cup mint, 1/2 cup basil, 1/2 cup chives, 2 tablespoons pine nuts, 1 tablespoon lemon juice, 2 cloves garlic, and 1 teaspoon kosher salt in a food processor and pulse to combine. With the machine running, slowly add the 1/2 cup olive oil in a steady stream. Turn machine off, scrape down the sides with a silicone spatula and pulse again until sauce is smooth. Add more salt or lemon juice as needed then either set aside until pasta is cooked or transfer to a tightly-sealed container and refrigerate for up to 3 days.
Bring a large pot of heavily-salted water to a boil and cook pasta 7-8 minutes. Do not overcook. Drain and transfer to a large bowl (don't rinse under cold water).
Add pesto and toss. This pasta can be served hot, room temperature, or cold, but I think it is best at room temperature. Cover loosely with plastic wrap (you can let it sit out for an hour or so).
When ready to serve toss in the pound of cherry tomatoes, drizzle with a little more olive oil, and sprinkle with the remaining 2 tablespoons pine nuts and chive blossoms or extra herbs.
If you'd rather have it hot, just toss the tomatoes in immediately and drizzle the olive oil and sprinkle the pine nuts and blossoms onto each serving.
If you'd like it cold, just stick it in the fridge, covered, after you've added the sauce. Then once it is chilled, toss in the tomatoes, drizzle with olive oil and sprinkle the nuts and blossoms on top.