No, there is no rule within WoD for this, you'll need to house rule.
There are any number of personality mechanics out there in RPG-land that provide different levels of prescriptiveness in their execution.
Don't Do That - Or Change Your Approach
To start off, you should carefully consider whether prescriptive personality mechanics are the right way to go. Many players hate them as they remove their volitional link with their character, and rightly so. It can harm immersion and basically lead to people thinking you/your game sucks. The annals of RPG campaigns are littered with this. So make sure you and your group are on board with this before proceeding. Here is a good overview of the differences between types of personality mechanic.
Are you just wanting to tell players what they should do? In that case, just tell them and have be unhappy. Having a rule for it just means you'll still be thwarted when the dice come up their way. GM fiat is GM fiat, don't try to shift blame to the system.
I'm not anti personality mechanics, but you should be using them from the point of view of providing better simulation. Or going full narrative; I always thought the Storyteller system had a hard row to hoe because it wanted to be more story/dramatist but still used a trad sim ruleset - you might want to look at fully narrative games like Fiasco where you are more controlling characters in the story, with less expectation of character immersion and thus personality mechanics become more "fun, like in the Sims" and less "hateful." That requires a major cognitive shift on the part of your whole group though.
OK OK, Now To The Mechanics
After the big caveat, assuming you want to do it, here's some options.
One approach is insanity type mechanics where you roll to see if you crack before doing something. Unknown Armies has a five-point stress/madness meter (violence, unnatural, helplessness, isolation, self) with "failed" and "hardened" scores. Stress stimuli have a degree. You don't have to check if it's under your hardened level. If you have to check and fail, you "freeze, flee or fight" in UA though I guess you're looking to remove the fight option. I know some people have adapted it to nWoD.
Pendragon has personality trait pairs where you do have to roll against them to overcome your nature. Here's the list and a short example of their use in play. You'd need to define what the general set of personality traits are you think is important - is it just the one "Morality = don't be a big gamer kill freak?" Do you want something more nuanced? What if different characters have different values, do you want one simple Morality stat to tell them all to act the same way?
Other games have implemented this in terms of specific traits, usually negative (like in Savage Worlds, if you have several disads you have to roll against them to not succumb to temptation). It sounds like you're making "still somewhat human" into a disad they have to roll against, (@Jadasc mentions this approach) which is fine at a point in time but will obviously result in them deliberately driving their humanity down to the point where it's not messing with them any more.
If you are just trying to give PCs a little help to overcome their less reflective nature, you don't have to use a mechanic that "just plain stops" them from taking actions. WoD has a form of this, the loss of Humanity every time you do something naughty that makes you eventually go all NPC is supposed to disincent you from going on kill-pages all the time.
Maybe it's not direct enough, or maybe bennies are better than slaps. Try awarding something - your game's equivalent of hero points - whenever someone follows their humanity instead of just doing whatever they want. A more complex version of this is FATE, where you get fate points for nerfing yourself according to your traits.
This approach is often much more palatable to players, because they are still able to perform actions if they feel very strongly about it, by paying in some virtual currency, but there's clear incentive to act in character that they will heed most of the time.