Please see this Nano Shield

This Nano shield has many servo ports, my question is, for 5 servos one needs at least 6 Amps of 5V DC, do I feed the 6 amp through the DC supply jack on the shield or, I still have to feed the servo s externally away from shield ?

Nano Sheild.jpg

If you would supply a link to the board so people know what you are dealing with would help a lot.
With 170 post's you should know how to attache an image and a link.

The shield likely has input for the separate servo power.
A link to the product would help us help you.

Just took a quick look at other sensor shield for the nano that look identical to this.
Most of those describe the barrel jack as alternate power for the nano, to be used if you are not supplying power through the USB.
Some similar shields have a jack for servo power. It looks like yours does not. I suspect that you are intended to supply power to the servos by connecting the separate servo power to the red and black pin of any unused channel.