Will guaifenesin help with nose congestion 400mg?

Yes. maybe.: Guaifenesin is widely promoted for sinus symptoms, bronchitis, and the common cold. It functions as a mucolytic, meaning it loosens phlegm and thins it out, making it easier to expectorate. It is not a decongestant, however. If congestion is your major symptom, something such as pseudephedrine (sudafed) will work better. The two ingredients are often found together in the same medicine(mucinex (guaifenesin) d).

No: Only med that so far showed helped is sudafed. It is found in "daytime cold medicine", there is slight help if you take antihistamines such as benadryl (diphenhydramine). Using nasal saline is safe.

Doubtful: Guaifenesin is for helping to loosen mucous. People normally take that to help with chest congestion. I have never found that it is very beneficial. Neti pots, saline nasal spray, prescription astelin NS, over the counter afrin nasal spray and pseudophed all work pretty well for this.