Combine 2 cups peas, eggs, 1/2 cup broth, 2 tablespoons chives, 2 tablespoons chopped mint, and salt in blender. Puree until smooth.
Pour into large bowl. Stir in flour.
Bring large pot of salted water to boil. Working with 1/3 cup batter at a time, and using rubber spatula, press spaetzle batter into pot through 1/4-inch holes of coarse grater, colander, or wide ladle. Boil each batch 3 minutes. Using strainer,transfer spaetzle to large colander; drain and place in large bowl. Toss spaetzle with 2 tablespoons margarine. DO AHEAD: Can be made 1 day ahead. Cover spaetzle and remaining 1 1/2 cups peas separately and chill.
Melt 4 tablespoons margarine inlarge skillet over medium-high heat.
Add spaetzle and 1/2 cup broth. Simmer until broth is almost evaporated and spaetzle are heated, stirring frequently, about 5 minutes.
Add remaining 1 1/2 cups peas,4 tablespoons chives, sliced mint leaves,nutmeg, and tomatoes. Toss until heated. Season with salt and pepper.