Niagara has alot of solids in it because it is a big, pulpy grape. Many white grape wines need bentonite in order to get them clear. We make alot of Niagara every year and have found a couple secrets---bentonite the primary and use a better pectinase such as Lallzyme C-Max.
I would wait and see if some clearing starts. Be sure you don't have it in a cool atmosphere--like a basement--because that can stall out the clearing action. Give it a couple months. If nothing is happening, sometimes an added dose of pectic enzyme can help. It could take up to 5 or 6 months to completely clear so be patient. If, by then, nothing much is going on you could try a dose of Super Kleer on it. But don't use the Super Kleer until then, because like others have said, the CO2 needs to come off of it too and by 6 months you'll have alot of the CO2 off of it. Don't manually degass this wine.