Laser-ablated osmium and ruthenium are reacted with nitric oxide and the products are isolated in solid neon and argon. The primary products in both neon and argon are the nitrosyl complexes M(NO)(1-3). Sharp, weak bands due to the mononitrosyl cations are also observed. The insertion products NMO observed for both metals differ in their stability relative to MNO; NOsO is more stable than OsNO whereas the reverse is the case for RuNO and NRuO. Density functional theory (DFT) calculations effectively reproduce the experimental observations and predict frequencies of chemically useful accuracy. The calculated isotopic ratios are also in very good agreement with experiment, showing that DFT correctly describes the normal modes in these molecules.