Preheat the oven to 450 degrees
Bring a large pot of water to a boil. Salt the water; add the broccoli rabe. Blanch for 2 minutes. Drain, pat dry and arrange in a single layer on a large rimmed baking sheet. Toss with the olive oil, garlic, chiles, fennel seed and nutmeg; spread in a single layer. Top with the sausage.
Roast 10 minutes. Turn the sausage and stir the rabe. Continue roasting until the sausage is cooked through, 10 to 15 minutes.
Transfer the sausage to a work surface and slice. Toss the rabe with the lemon juice. Divide the rabe and sausage among plates. Serve with the warm bread.