How can I disguise my own name (for my screen) in chat on a recording?

I’m starting a channel for gaming, and I like my current Minecraft username, however if I change it to match my new one bad things will occur (and I don’t want to buy a new username because then I have no stats).

Is there either:

• A setting I can change that will modify how I see my own name in chat; like /nick from Hypixel but without /nick?
• A text replacement mod that changes my name – wherever it is in chat – to a different name? (e.g. Someone says "Hi JB" it’s changed to "Hi mr_big" on my screen?)

Kinda not sure if this is on-topic for here, but I’d love to know any ways to do this.