A 3-D flow in a MEMS-based micronozzle has been modeled using the DSMC method. Two potential propellant selections: a solid mono-propellant LAX112 and a hydrogen-air mixture, have been compared at stagnation pressures 0.1 and 1 atm. The corresponding Reynolds number of the flow varies from 30 to 440. For both pressure and propellant conditions, the flow is strongly influenced by the friction and heat transfer losses. The calculated specific impulse is about 170 sec for a stagnation pressure of 1 atm and about 120 sec for 0.1 atm. The discharge coefficient varies from 0.86 to 0.97 depending on the Reynolds number. The calculated infrared spectra for the LAX112 propellant suggest that the infrared signal from such plumes can be detected and used to determine the influence of the cold wall boundary layer on the flow parameters at the nozzle exit.