Ahsoka has Snipes, given to her by Anakin. It comes from her being contrary to him in the first meeting, i.e. acting snippy. She called him Skyguy right before, so I can't blame Anakin one bit.
Jessica has Hamsandwich Woman, which comes from Carol due to Jess's hunger for a good sandwich.
Oliver Queen calls Tess 'Mercy' due to the fact that she saved his life the first time they met. It's also a play on her last name and that Tess was created partially to fill the role of comic character Mercy Graves.
Kylo doesn't necessarily have a nickname that he is aware of. One might call Kylo the nickname for Ben.
Creed doesn't have a nickname so much as a code name, Sabretooth. He's not overly fond of it. He was given it because his body language and actions often resemble a big cat, and he's got the teeth to go with it.
Yamato gets 'Yama' from Taichi -- and no prizes for guessing where that comes from -- but I don't think anyone else uses a nickname for him. The closest anyone else gets is Takeru, who refers to him as 'aniki' most of the time, but that's not a nickname so much as it is an honourific.
Wilson isn't a huge fan of being called nicknames, and doesn't have any canonically anyhow. (He is one of four playable characters whose names start with Wil, at least if you count one of the other Wils by legal name instead of the name he goes by, so in my opinion it's a good thing that nobody's tried to shorten Wilson's name to that.)
Technically, Bastion is a nickname. They weren't given a pronounceable personal name so they go by a couple different short forms of the name of their model.
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Jessica has Hamsandwich Woman, which comes from Carol due to Jess's hunger for a good sandwich.
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Kylo doesn't necessarily have a nickname that he is aware of. One might call Kylo the nickname for Ben.
Creed doesn't have a nickname so much as a code name, Sabretooth. He's not overly fond of it. He was given it because his body language and actions often resemble a big cat, and he's got the teeth to go with it.
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Technically, Bastion is a nickname. They weren't given a pronounceable personal name so they go by a couple different short forms of the name of their model.