Fun fact, in most games, Initiative is actually pretty pointless past the first round as thereafter everything enters into a rhythm or a predictable rut.
M.A.S.O says “fuck that.”
Initiative isn’t rolled for or set like some games. It is Seized, which means whoever wants to go next, can. On the first round of combat, someone Seizes the “first” position. If two people want that position, one or the other can concede or they roll off. A Seize roll is 3d6 + any modifiers - note that Nerves is not a modifier by default. Ties result in another roll off. The process repeats until everyone has Seized a place in the initiative order. If a player fails to Seize the initiative, they take a cumulative -1 to all Seize rolls, all of which can be removed by Deferring to a lower initiative order as they back off and regroup.
Players can remain in this initiative order for the remainder of combat, or they can grow a set and alter the order.
At any point in a round, a player that hasn’t gone yet may try to Seize a higher initiative position or may Defer to a lower one. Deferring simply means dropping to a lower initiative position of their choice. Seizing a new position is a roll-off, with some extra steps. The seizing player rolls as normal and the “defending” player gets a bonus based on how many positions in the combat are between them and the seizing player - this is supplied by the GM. Pay attention! There might be useful information if the GM gives you a number that conflicts with your own understanding of the combat.