Obakoso (also Obakosso, Yoruba Oba kò so) is a praise name of Changó, and according to EcuRed also one of his paths (caminos): Shangó Obakoso. It is not a separate batá toque.
Oba kò so means "the king did not hang". The name refers to the tradition about Shango's end as king of Oyo, before he was worshipped as the orisha of thunder. The phrase also became known through the play Ọba kò so ("The King Did Not Hang") by Nigerian playwright Duro Ladipo, first staged in Osogbo in 1963 and later toured through Europe, the Americas and Brazil.
In Cuba, EcuRed lists Obakosso among his names, alongside Changó, Shangó, "Señor de los Truenos" and Yakutá. Changó has dozens of paths there; Shangó Obakoso is second on the list.
None of the sources we consulted mention a batá toque named Obakoso. The toques that do belong to Changó are Alujá (also Aluyá), Bayubá and Chachalokafún; see the Changó toque. Changó is also regarded as the owner of the batá drums.