The Chosen One gets this title by joining one of the four mafia families in New Reno and having an Intelligence above 4. For each mafia family there is a chain of quests, upon the completion special ones they can become a Made Man of that family, even as a female character.
Turning against the family will cause your Made Man status to be removed.
For each family boss, there's a way to assassinate them without getting blamed for it, and killing a boss "silently" or in these special ways will not remove the Made Man title.
It's possible to become a member of almost all mafia families, by not becoming the Salvatores' Made Man until the quest from Mordino to kill Salvatore has started.
If a family quest is active when a family has turned hostile, the quest will be set to failed in the quest list.
Although the in-game description says "you look great in a fedora," no wearable fedoras are present in the game, and they are only seen worn by casino bouncers.
The sentence for paralyzing Jagged Jimmy J is not a typical sentence (normally poorly constructed and difficult to understand) said by low-Intelligence characters, instead looking more like something that an intelligent one could say.
If you attack the raiders underground base south of vault city and later become Bishop's Made Man, he will confront you and become hostile.