Supersonic chemical oxygen iodine laser (SCOIL) hasrecently proved itscapabilities against projectile targets such as missiles and rockets in the tests performed with ABL system. It is primarily a chemical based gas laser system involving extensive gas dynamics for achieving lasing action. COIL (l= 1.315 mm) is conducive for both defenseand industrial applications and the beam is optical fibre compatible. One of the chief components of a SCOIL device is the supersonic nozzle system which not only produces the desired cavity conditions in terms of Mach number and cavity pressure but is also responsible for efficient mixing of lasing [I2 + N2] and pumping media [O2 (1Dg) + N2]. The supersonic nozzle to a large extent controls the pressure recovery potential of the laser system and thereby the system volume. The present study discusses the performance of three nozzle configurations viz, slit, advanced/ ejector and winglet nozzle. The comparisons have been made in terms.