This stage isn't super challenging, and is definitely the easiest level in Dead End Night.
Aside from that, it can take a while. Bring area attackers like Paris Cats to clear out the endless peons. When the boss arrives, let him get close to your base. Use Crazed Titan and Jamiera to damage him. Your best chance to damage him is after the Cat Cannon is fired. You should win after a while.
At the beginning, spawn one Crazed Brave. Then when the first boss wave comes out, spawn a Crazed Sexy Legs and one Crazed Wall. Build up your Worker Cat. Afterwards, when your Worker is maxed, spawn everything. If you're lucky, Nyandam won't even get an attack in because he takes so much damage from the Anti-Reds and is knocked back by Jamiera.