Sausage and Escarole Over Toast

Name: Sausage and Escarole Over Toast
Ingredients: 3 tablespoons olive oil, plus more for drizzling; 1 pound fresh sweet Italian sausage links; 2 medium onions, thinly sliced; 4 garlic cloves, thinly sliced; ½ teaspoon crushed red pepper flakes; 3 cups low-sodium chicken broth; 1 head of escarole, leaves separated and torn (about 8 cups), divided; Kosher salt, freshly ground pepper; 2 tablespoons fresh lemon juice; 4 thick slices country-style bread, toasted; 1 Fresno chile, thinly sliced into rings; ½ cup finely grated Parmesan