In the sense of a 'plague'? No, a4android is right, that's not likely to happen (though it isn't impossible, the only difference between an illness and a plague is scale).
However, there are ways to get the effect you seek without bending things in the least. Let's say the noecebo that gets started comes with a self-reinforcing component? A poisoning of the mind, so to speak. All you need is for a few factors to be put in place.
BEAR IN MIND! This answer is based on the concept that a noecebo is purposely pre-planned and injected into its victims with full knowledge and intent to do so.
So you want to create death and destruction on a grander scale? Let's see how to best do this. The 'virus' may or may not have directly lethal results, but it isn't impossible for this to happen. The mind is a powerful thing, all you need to do is make the mind believe what you are selling, and you can have said mind stop the heart, ergo: death.
Patient 0, as it were. You need someone that is not immune to such a concept, which is tested by starting them out with a much less severe variant. Once you have the first victim believing that you have that power over them...
So you have your victim in your power. Bring out said victim in front of a crowd and carefully explain what is about to happen. Make sure these people are influential and preferably hard to convince. It makes for far more credible publicity afterwards.
Once they understand that they are 'already in your power', offer the victim the covert 'command' (i.e. the predetermined 'stop your own heart' command). Make it something commonplace, like snapping, whistling, or a common word. You want this to be widespread, after all.
Now that you have your first spread going, it will start to attract more and more attention. People will start ranting and raving in the streets. Trustworthy people, people that can affect a wider audience for you. They will tell their stories, they will say what you did and what they believe you are capable of. In their panicstricken state, they will not realise they are doing your work for you.
If you set it up right, others will start to believe it's true. That will do one of two things: either they will believe they have it too, or they will start to try to preemptively cull those they believe that are infected to 'stem the spread'. Now that the one town is in utter anarchy, you need to:
While the media starts covering your ground zero, you go and start the same process in another town far, far away. Repeat the abovementioned steps a few times, let this become an utter frenzy. More and more people that are susceptible will believe they have it, and more and more people who aren't will fear they might be the next victim.
Well, either they 'cull the infected', or the 'infected' spreads the 'disease' more and more. If at any point you notice that the spread is slowing, repeat above mentioned steps until either you are caught (which can be planned for and thwarted if you are creative) or until you get the result you are aiming for.
And when things are at their darkest, you can come in as a knight in shining armour. Offer a sugar pill, using the placebo effect to stave off the worst of it. Just be sure to charge exorbant prices, and 'run out' often enough that they'll become even more desperate when you decide to sell.
Things to bear in mind:
I am not an evil person. I'm just misunderstood.
This is based on mob mentality, which is quite effective in the right circumstances. Just look at the Y2K bug for a very unsettlingly real example.
Whether you use a substance to 'infect' patient 0 or the first crowd is irrelevant. That's the slight of hand to get the effects you want.
Do not credit me in your master plan. If the CIA, FBI, Interpol, or anyone tracks me down, I can (and will) honestly say I've never met you.