If you are asking if the only cards you can install on the board and SLI are nvidia cards, then the answer is yes.
But you have to remember that it only applies if you are installing 2 nvidia cards and planning to SLI them.
If you plan on running only one card, you can install either an ATi card or a nvidia card. If you are using windows7 as your OS, you can have both an ATi and Nvidia card with multiple monitors.
( I am happy that they brought that feature back..)