Here's why they don't sell a Micra in the U.S:
(Source:
Cheap Wheels: The Least Expensive New Cars of 2015 )
The Versa has been the top-selling subcompact in the U.S. for years, and it's also the cheapest new car (MSRP). Nissan already has a success story in that car and would probably end up cannibalizing their own sales if they added the Micra to their U.S. lineup.
In Canada, the sedan never sold well, and it was cancelled when the Micra came out. You'd think the Micra would steal Versa Note sales, and it definitely has. But their
combined sales have increased to the point Nissan now has the biggest share of the subcompact segment.
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PS: the 1.2 in the Euro Micra is supercharged (or n.a.)