| nscr | Nitro Screen Resource |
| nsd | BLAST Nucleotide Database |
| nsd | NRG Systems Symphonie Data |
| nsf | Lotus Notes Data |
| nsg | Nessie Saved State |
| nsi | BLAST NSI Data |
| nslloc | Mac OS X Finder NSL Location Data |
| nsm | AQUA NOE Distance Restraints Summary Data |
| nsm | NESticle Movie |
| nsmp | Nord User Sample |
| nsp | Nintendo Switch Submission Package |
| nspe | Navicat for SQL Server Exported Table |
| nspl | Netscape Navigator Plug-in |
| nsps | Navicat for SQL Server Structure Synchronization Data |
| nsq | BLAST Sequence Data |
| nsr | EMC NetWorker Directive File |
| nsx | Apollo HiPer-SIx Database Index |
| nt2 | NinjaTrader Level 2 Market Replay Data |
| nt3 | JB BAHN Layout Data |
| ntar | Network Trace And Retrieval Dump |
| ntb | Tecplot License Data |
| ntd | NinjaTrader Database |
| nte | Holonote Note |
| ntf | Lotus Notes Template |
| ntfp | Nitro File Palette |
| ntft | Nitro File Tiles |
| ntg | NTGsim Data |
| ntm | Navitel 2.0 Map |
| ntm | NinjaTrader Market Replay Data |
| nto | NTOScanner Data |
| ntr | Netrun Executable List |
| ntv | PatternSmith Native |
| ntw | Lode Data DA Network |
| ntx | Clipper Database Index |
| nu3 | Norton Utilities Backup Data |