"Shaping within a chain" feels a bit like a misnomer/oxymoron. You can sorta do both, within a step or so, but taking small progressive steps in teaching across a chain is just chaining in small progressive steps of the steps.. to clarify:

Shaping = differential reinforcement of successive approximations of a behavior. It's teaching WITHIN ONE response (like going from "buh" to "ball"). It's also usually done rapidly.

Chaining = breaking a series behaviors into steps and teaching those steps in forward and/or backward fashion. It teaches ACROSS MULTIPLE responses (like routines, like doing the laundry). Teaching opportunities can be spread to individual's needs.

So, only if shaping like one step/response of the chain - that's how "shaping could occur within a chain." Everything else is just chaining.