Nemotron 3 Ultra and GPT Chat Latest are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Nemotron 3 Ultra, from Nvidia, has a 262,144-token context window and is priced at $0.50/M tokens input, $2.20/M tokens output on OpenRouter.
GPT Chat Latest, from OpenAI, has a 400,000-token context window and is priced at $5/M tokens input, $30/M tokens output on OpenRouter.