"can I just attach CORD ONTO THE LEADS OF THE BALLAST with some kurneys(plastic nuts?"

That's the idea. Wirenuts, BTW.

It would be nice to wire them in and add a light switch, but technically all you need is a good three prong AC cord.

I agree with Jkirk. Just remember to firmly attach the power cord ground to the metal case. There might already be a ground lug with a green wire from the ballast, you can use that. Match black ballast wire with black power cord wire, same thing for the two white wires. And make sure the power cord has a rubber or vinyl grommet with strain relief where it goes into the case to protect against cut wires.

Light switch? Plug it into a timer and then you don't need a switch :)

"And make sure the power cord has a rubber or vinyl grommet with strain relief where it goes into the case to protect against cut wires."

When it comes to strain relief, there's a trick to that.

I can't quite recall the name, but there's a knot we used to use in Electronics classes. We'd run the cord in through the case, tie the knot in the cord, and since the knot was larger than the cord that protected against the cord getting yanked out of the case and causing a short.

You separate the two wires from the cord and give yourself two inches of wire to work with.

Pull the cord through the hole in the case and give yourself some slack.

Hold the cord with wires sticking out facing away from you.

Now, take the right hand wire and bend it down, then back toward you, then under the left wire. Pull a loop and bring the end of this wire back up around the left wire to point forward.

Hold the loop in place with the thumb of your right hand.

Then do the next step with the left hand wire without disturbing the right hand loop.

Pull this second wire OVER the right hand wire loop, around it, and bring the end of this second wire through the loop formed by the first wire so the wire points forward.

Pull the knot tight.

Now, if you did it right, you've got a strain-resistant knot that won't pull through the hole if somebody tugs on it.