Yes, if President Trump vetoes the bill, the Senate will override his veto. If not, the Dems will just reintroduce the bill next year.
So President Trump is right to veto it. Since he lost the election, he can ignore his critics. He wants to give a parting gift to those fans of his who feel that for historical reasons those names -- and statues -- should be kept.
In any case, in the coming decades, the population profile of this country will change drastically, so it's only natural that many names of many things will be removed in favor of more politically correct names.
No big deal.