This is an opinionated answer, but I’ll make it anyway.
Meteor is a good solution for implementing chat, because of its reactivity.
It is a very simple exercise to build a chat interface, and it works very well. Meteor has support for IOS and Android too, and the build system makes that relatively easy.
Many Meteor apps have chat as a feature, which backs up this recommendation. Other technologies can do it too, but as far as I know there would be much more work involved in doing it