Dana White tells TMZ Sports ... the UFC will donate $1 million to help the victims affected by the Las Vegas shooting. 

The UFC honcho said Vegas is his town -- it's where UFC is based and where he lives -- and he feels it's his duty to help the city recover in any way he can. 

White is calling on other Vegas moguls to pony up some dough as well -- and wants people who live outside the city to know there's one big way they can truly help out.