After reporting from a well placed source that NVIDIA would be supplying a Pascal-based Tegra design for Nintendo Switch (Derek's super detailed, super awesome review on the Nintendo Switch is here), we've been proven wrong - thanks to a new teardown by Tech Insights.
The teardown shows that Nintendo used a stock Tegra X1 processor - not a custom Tegra processor, and a Maxwell-based GM208 GPU. Last October, NVIDIA teased that the Nintendo Switch would be powered "by the performance of the custom Tegra processor". But the teardown shows that it's nothing custom, and a stock Tegra X1 processor instead.
Tech Insights' report states: "After subsequent processing of the GPU from the Nintendo Switch, we have determined that the processor is the NVIDIA Tegra T210. The T210 CPU features 4 Cortex A57 and 4 Cortex A53 processor cores and the GPU is a GM20B Maxell core".