No this sentence is very peculiar. It means exactly what is translated.
Where are you carrying those sanwiches? To school?
No, I am not carrying sandwiches to school.
Niosę is the "right now" kind of verb, along with idę, płynę etc.
Nie noszę/nie biorę/nie zabieram kanapek do szkoły are what would be translated I do not carry/take/bring sandwiches to school.