Hm, it's not strictly limited to solidifiying chakra, and it can be involved with elemental chakra as well.
Shape manipulation, as the name suggests, allows you to shape chakra, whether it be elemental or normal. It also involves direction, speed, and anything affiliated with its movement and shape, basically.
Nice! To elaborate more on Nature transformation, it involves changing the nature of chakra into the nature of a certain element in order to perform elemental ninjutsu. For fire, you would manipulate your chakra to be as hot as possible so as to mimic the properties of fire.
Anyways, we're almost at the techniques.
If you were to perform nature transformation on chakra to make it into wind chakra, how would you do it? o-o Like, let's use the previous example. If you wanted to make fire chakra, you would make your chakra heat up immensely, but what about wind?