I did some snooping, and found out that P&G changed the formula after 2006. The original formula used to contain a decongestant called pseudophedrine. A law passed in 2006 that made all products with this decongestant be kept behind the pharmacy counter led P&G to change the formula so that Nyquil could still be kept out on the shelves. A version called Nyquil D was available behind the counter that still had pseudophedrine in it, but in September of 2010, it was discontinued.
I noticed that the slogan, "The nighttime, sniffling, sneezing, coughing, aching, stuffy head, fever, so you can get your rest medicine" has changed, too- I believe it now says, "the nighttime sniffling,sneezing, coughing,aching, best sleep you ever got medicine". They left out the "stuffy head" part because they no longer include a decongestant.
Nyquil Sinus does contain a decongestant called phenylphedrine, but it is not as effective as the original formula and is available in liqui-cap formula.