https://apply.joinsherpa.com/visa/northern-mariana-islands/chinese-citizens
You need an ETA for Northern Mariana Islands if you have a Chinese passport
Visa options for Northern Mariana Islands
CNMI Travel Authorization (EVS-TAP)
Travelers need a travel authorization to visit Northern Mariana Islands for Business or Tourism for a maximum of 14 days. The CNMI Economic Vitality & Security Travel Authorization Program (EVS-TAP) is an online application that determines the eligibility of visitors to enter Northern Mariana Islands. Once the application is approved, travelers receive their CNMI EVS-TAP confirmation electronically. Travelers must have a round?trip ticket with a confirmed return date within 14 days. Otherwise, a paper or embassy visa is the only type of visa available to these travelers. The visa is typically a stamp or sticker added to the passport. Travelers must obtain this visa from a local embassy, consulate or visa center before traveling.
This is not offered by Sherpa. Apply directly with the government.