Without constraint, there are $\boxed{11!}$ ways to line up these people.

When people with same nationality cannot stand next to each other, we note that six Chinese must be separated by the five non-Chinese. Hence, the result is $\boxed{6!\times 5!}$ by considering the following steps:

1. Line up the $6$ Chinese: there are $6!$ ways
2. Line up the $5$ non-Chinese: there are $5!$ ways
3. Merge these two lines by inserting one non-Chinese into the interval between two Chinese