The lyrics of "Sto lat" with "niechaj" would match perfectly, but the melody and especially rhythm is different.
I'm very certain of the triple meter. It's either like I played:
la la | la la | laaa
or possibly:
la la la | la la | laaa
"The melody matches with "Sto lat", however there is an extra note (syllable) between "niech" and "żyją". It fits when you use "niechaj" instead, but that would be rather uncommon version.
Niech [-] żyją nam
Niech [-] żyją nam
W zdrowiu szczęściu pomyślności
Sto lat niech żyją nam
W zdrowiu szczęściu pomyślności
Sto lat niech żyją nam
This is very popular and apparently it's being sang to the melody of "Za górami, za lasami". As common with folk songs, they both don't have an author.
nonoseacrest
Il y a 667 jours
MattLmao
Il y a 668 jours
MattLmao
Il y a 669 jours