nissen is the masculine singular definite of nisse.

nisseN

Kven

nissiN; nisseN

Norwegian Bokmål – Kvendict-nob-fkv/src/N_nobfkv.xml:5370Edit on GitHub Suggest

juovlanigáN

Norsk-nordsamisk ordbokdict-nob-sme/src/N_nobsme.xml:169582Edit on GitHub Suggest

Case	Sg	Pl
Indef	nisse	nisser
Def	nissen	nissene