The closest alternative to GPT-5 Nano is Solar Pro 3 — comparable intelligence (25.9 vs 25.9); for a cheaper option, Nemotron 3 Ultra (free) runs Free/M vs $0.050/M; for more speed, gpt-oss-120b (free) hits 554 t/s; and the best open-weight substitute is MiniMax M3.
Solar Pro 3 is the closest alternative to GPT-5 Nano, with an Intelligence Index of 25.9 (GPT-5 Nano scores 25.9) at $0.150 per million input tokens.
Yes — Nemotron 3 Ultra (free) costs Free per million input tokens versus $0.050 for GPT-5 Nano, while staying within ~8 points of its Intelligence Index.
MiniMax M3 is the strongest open-weight alternative to GPT-5 Nano — downloadable from Hugging Face and self-hostable, scoring 54.7 on intelligence.