I say no,It's mainly for keeping Phosphates low and it's good for about a week.Get Phosban or the better stuff Rowaphos.For Nitrates,keep up on your water changes and a good skimmer.
This includes carbon and GFO. I don't know how good the carbon is but the GFO is to remove phosphates.
You could get phosban or any other GFO and buy your own carbon and probably save money.
Are you using a reactor?
Chemipure is a mixture of GAC (granular activated carbon) and an ion filter media. Chemipure Elite adds a GFO. A lot of people with nano tanks, including myself, use one or the other. I think the GAC and ion media do a great job. I don't think the GFO in the Elite does much as there is too little of it and there isn't much flow through the bag.
I've never read anything that mentions GFO leeching back into the system. That is one of the reasons it has a lot of appeal in the hobby. Maybe some GAC can if it's low quality.
If you have the space I would run pure GFO in one reactor and GAC in another. They have different flow rates and absorption cycles. This way you could maximize the benefits of both.