| Abbreviation | Definition |
|---|---|
| NISA | Nuclear and Industrial Safety Agency |
| NKS | Nuclear Knowledge Summit |
| NLR | nuclear Lindblad resonance |
| NLS | Nuclear Localisation Signal |
| NLS | Nuclear Localization Sequence |
| NLSO | Nuclear Licensing and Safety Office |
| NLSU | Nuclear Large Sub Unit |
| NMAC | Nuclear Maintenance Application Center |
| NMC | Nuclear Management Company |
| NMI | Nuclear Medicine Imaging |
| NMLI | Nuclear Medicine Leukocyte Imaging |
| NMM | Nuclear Mod Mangler |
| NMR | Nuclear Magnetic Resonace |
| NMRI | Nuclear Magnetic Resonance Imaging |
| NND | Nuclear Nonproliferation Division |
| NNDC | National Nuclear Data Center |
| NNE | Networking Nuclear Education |
| NNES | National Nuclear Energy Series |
| NNK | Non Nuclear Kill |
| NNL | Naval Nuclear Laboratory |