Not the same kind, though the difference was subtle, and maybe not an important distinction to most people. In ICQ, you sent discrete messages back and forth. You could (I believe) look at the last message while replying, but you didn't have a chat history integrated into the same window where you replied. I used both ICQ and AIM in the '90s and early 2000s, even talking to the same people, and the interactions felt very different. ICQ felt like it was between email and AIM in the communication spectrum: obviously interactive and real-time, but each person tended to say more in each message. AIM's style encouraged more call-response conversations.

I point this out because I think it's an interesting case of user-interface design influencing use, even though on the surface they're both "chat apps."