From Hyginus' account:
NYSUS: When Liber was leading his army into India, he gave the authority over his Theban kingdom to his nurse Nysus until he should come back. But after Liber returned from there, Nysus was unwilling to yield the kingdom. Since Liber didn't want to quarrel with his nurse he permitted him to keep the kingdom until an opportunity should come to recover it. And so, three years later, he made up the quarrel with him, and pretended he wanted to celebrate in the state the sacred rites termed Trieteric, because he performed them after the third year. He introduced soldiers as Bacchanals in women's dress, captured Nysus, and recovered his kingdom.
[...]
LIBER: Liber, son of Jove and Proserpine, was dismembered by the Titans, and Jove gave his heart, torn to bits, to Semele in a drink. When she was made pregnant by this, Juno, changing herself to look like Semele's nurse, Beroe, said to her: "Daughter, ask Jove to come to you as he comes to Juno, so you may know what pleasure it is to sleep with a god." At her suggestion Semele made this request of Jove, and was smitten by a thunderbolt. He took Liber from her womb, and gave him to Nysus to be cared for. For this reason he is called Dionysus, and also "the one with two mothers."
[...]
SEMELE: Jove desired to lie with Semele, and when Juno found out, she changed her form to that of the nurse Beroe, came to Semele, and suggested that she ask Jove to come to her as he came to Juno, "that you may know", she said, "what pleasure it is to lie with a god." And so Semele asked Jove to come to her in this way. Her request was granted, and Jove, coming with lightning and thunder, burned Semele to death. From her womb Liber was born. Mercury snatched him from the fire and gave him to Nysus to be reared. In Greek he is called Dionysus.
While I love the concept of Cadmus initially naming his grandson Nysios before sending him to the Nysian country to be raised there the idea that Dionysus might've been named after his nurse is endearing as well.
