1. Nd6! cxd6 2. Nxc6+ Kd7 3. Nxb8+ Kc7 4. Qxe6
The point of 1. Nd6 is that it threatens the discovered attack Nxc6+, followed by Nxb8+ and/or Qxe6.
1. Nd6 Qxd6 2. Nf7+ followed by Nxd6
The "7-Skills" Chess Training Model. Get your free copy here...