Or HaChaim on Numbers 7:13/אור החיים על במדבר ז׳:י״ג

1 וקרבנו, and his offering, etc. The justification for the letter ו in this word is found in what we wrote about every offering consisting of two aspects in our commentary on the word המקריב. It is a reference to the hidden spiritual aspect of the sacrifice which preceded the Torah's revelation of the material aspect. One may also simply understand the letter as alerting us to the many qualities Nachshon possessed in addition to initiating the kind of offering the princes brought at this time.