My suggestion is to commit to keeping the loud music inside the nightclub. So keep it in the club. To keep the loud music in the nightclub, hire an acoustical consultant to help you implement as many of the following suggestions as you can afford. The suggestions are based on the principles of isolation and insulation. Isolation works by avoiding direct acoustic coupling so the transfer of the loud music to the outside space is reduced by the benefit of an impedance mismatch.
Insulation absorbs and neutralizes acoustic energy to keep it from radiating out of the nightclub.
Your acoustical consultant will explain those principles in more detail especially as they relate to design of your space. When the space is open during the day and there's no loud music use the tracks to slide the sound absorbent materials away from the window. Isolate the stage from the floor of the room with acoustical insulation material. Isolate all speaker systems from the floor of stage with acoustical insulation material or hang them from the rafters. The idea is to build highly reflective false walls and ceilings.