which are the good camcorder or DSLR to make video tutorials or MOOC to show on wide screen using projector?
The SONY HXR NX1 is a staple of capturing professional-grade content that can be produced on its own or incorporated into other productions.  Yes, there are higher-end cameras, but this is a solid choice for a pro-level classroom.  I have seen this camera in many classrooms.  With a good operator, and a decent sound-recording system, you will be in the top quintile of production.

The Panasonic HC-850K has a marketing gimmick of being able to produce two video views at once, such as a wide view and a zoomed-in view.  I have not used this camera, but its relatively low price and very modern technology make it a sensible choice for somebody looking to prototype a solution, learn the limits of the camera, and then buy what's really needed without losing too much investment.

The Logitech C920 HD Pro Webcam is suitable if the scope of your subject is basically just sitting in front of it.  If your talking head talks while seated in front of a computer, great.  But if your talking head talks and walks (such as in front of a lecture board), it won't suit.  Similarly, if your demonstration requires aiming the camera at anything more interesting than a talking head, you will likely find the ergonomics of the webcam to be not worth the hassle.

A Nikon D5200 24.1MP Digital SLR Camera (and any other SLR) is probably a terrible choice for your application.  These cameras really are optimized for still shooting.  Yes, they do shoot video.  Yes, the video sounds like it has a good spec.  But the reality is they come with all sorts of limitations (such as a maximum 29 minute recording time).  And you need to get much more expensive and much less capable lenses to fill a sensor size you don't need/can't use for video.  DSLR video is always at least one step below a similarly priced true video camera.  And the lenses cost extra, compared with many video cameras, which have them built-in.

The Kodak PlayTouch Video Camera (and similar) are popular for "flipped" classrooms.  I.e., classrooms where both teachers and students can contribute video content to the overall experience.  If your MOOC idea involves student-contributed content, then giving everybody a level playing field can be a good idea.  But if you want to "produce" something, the limitations of these cameras will drive your producer crazy.