Sería muy bueno que se pueda reaccionar a los comentarios del chat, como emoticones de felicidad, tristeza, enojo, etc. A veces no es necesario responder un comentario y decir que está gracioso, basta simplemente con que se sepa que lo fue.

Que los usuarios puedan tener la opción de hacer click al comentario que más les gustó y de alguna forma hacerlo resaltar en tiempo real(ej: más grande)
El streamer lo ve más facil

Yes, keep it simple though like just the basics:

Laugh,appreciate,depreciate,roll eyes/groan, mad, maybe a COUPLE others

As for the design I imagine 2 concepts: first is the classic/obvious emojis appear with a number next to them.
try to keep the options to ~6 reactions.
Also maybe cap the reactions to 10 so in bigger chats its less likely to cause attention anxiety

But a better option might be to have it be an animated bump on your comment. Someone clicks the comment,selects one of two reactions: positive or negative and then the author (or everyone) sees the comment bounce/shake/flash/confetti or shadowblink/*****&crumble/submerge/explode.

The biggest issue with this I can imagine is a LOT of new chat clutter, and its a huge waste of energy/bandwidth (remember every bit of data costs energy to send and receive).

Add the opportunity to react with emojis to a chat message, like on Discord (maybe only for Mods and VIPs)

for a previous chat txt, it would be great to have just an emoji response w/txt like slack. Some times people chat some funny things would be great to do a lol, heart, or some other emotes. I am sure Twitch has an emoji dept.

THIS! Why i need to reply with "LUL/Kappa/etc." or just spam emotes when i could just hit the emote directly for the comment

On Discord, you can react to a message with an emote or emoji. This allows people to react to a comment without clogging up the chat with "LOL" or "yes/no", etc. The streamer would be able to opt-in to it to prevent it when it isn't wanted.