faucet connector to male nipple?

I have a flexible faucet hose with a 1/2 FIP connector. Can I connect this to a 1/2 male thread, such as on a male nipple. That's what comes out of the ball valve for the cold water supply. The threads seem right and the rubber gasket would seem to seal against the end of the nipple, which is smooth.

Yes, because the flex connector uses a cone gasket or similar, it will connect to a pipe nipple. The flex has straight threads, but they will snug up OK on the nipple.