Arduino Nano Power

Hi,
I connected a 9v battery to the VIN port on my Nano and it powers up the board but it doesn't turn to my leds that I have connected to the board. But my leds do work when powered through the usb port. Could I connect a 9v battery to the usb port?

Thanks

oisinw87:
Could I connect a 9v battery to the usb port?

No.
Tell us how you have the LEDs wired up.