I believe im beginning to get a cold, i would like to know if i can drink niquil and take my 50 mg of sertaline tonight.?

I would not: The cough suppressant (dextromethorphan) in nyquil can interact with the sertraline to increase the risk of serotonin syndrome, a serious adverse reaction common to all ssris (such as zoloft, aka sertraline).

Yes: No reason not to treat the symptoms of a cold with medications which will decongest you, help you sleep and diminish coughing. No reason to discontinue sertaline.