Have any of you learned to teach pitching?

I believe you can but you'll need quite a time investment..of course those who are really good at it never stop learning or refining technique..so if it is a desire..set yourself on the path and commence learning.
There are some out there who believe that they were able to somehow short circuit the learning curve (Miraculously became "expert" after just looking at pictures or having one experience)...don't be fooled, nothing beats the time effort and commitment to learning.
Just as you believe that you've picked up nuance in hitting, over time you'll see it in pitching. I'd suggest attending some college level clinics or if you are really committed attend an National Pitching Association certification clinic (not cheap but very meaningful)..it won't be in a DVD that you'll learn this skill.

JD, you have a PM.

The NPA's coaches certification JD referred to is an excellent source of some of the best information available. You will learn a lot from it but you will not learn everything they teach. You will continue to learn by trying to teach/apply what was taught and by gaining experience figuring out what works with different pitchers in different situations versus what doesn't work. Then you attend the coaches certification again and you hear things slightly different or your experience lets you pick up on things you missed the first time or understand things differently than you did the first time. This is how, as JD pointed out, it takes time. And it's why you must be willing to continue to learn.

I've been through the NPA's certification every year for the last 5 or 6 years. They've alwsys got something new to offer. And it's a very positive environment attended by people from all levels who are very passionate about pitching.

And, no, I don't get anything by recommending the NPA's certification clinic.

Roger that! Experiences in baseball are the ultimate payoff. As all big leaguers and others who have been in the game for so long, "You never stop learning". Having no background knowledge in mechanics, situations, feel, and all other nuances will take a great amount of time, training, and observation. No situation is alike because all mechanics and players are different in there own way. Yes there are core ways to go about things but unfortunately there are no universal mechanics and that is what makes the game so great.

From Quisenberry, to Randy Johnson, to Lincecum. All different styles, shapes, and sizes. But take all the courses and do the observations and beyond just trying to be able to teach it, you will find that your love for the game will grow and you won't believe your eyes when you get to understand how to slow down the game and see it in a different way.

I've been doing it most of my life and I still can't teach it.