Not at all. Vietnamese are a mix of proto East Asian who migrated from Southern China and ancient Southeast Asian Hunters. They received the East Asian looks from these proto East Asian farmers, not from mixing with Han Chinese.
Here are pure blooded Tai Kradai Laotian that are not mixed with Chinese. Do they look like North Vietnamese or East Asian?
North Vietnamese mainly got their East Asian looks from the Kra-Dai and proto East Asian people. They didn't get them from mixing with Chinese. Vietnamese are genetically closer to Zhuang than Southern Han Chinese like Cantonese.
Guys, please stop attributing Chinese looks and cultures to being related to or descended from Han Chinese. That's like saying some Levantines Middle Easterner who look European are descended or mixed with European or Southern European. Only very uneducated and stereotypical people do that.
Only on the internet, kazakhs are Chinese, Mongols are Chinese, Japanese are Chinese and Korean are Chinese. No sane people think that way. It's time to accept that East Asian looks or cultures are an umbrella group that encompass vast territory and numerous ethnic tribes.