I opened the iOS nanodegree page:
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The core courses will bring you from zero to hero in developing industry-quality iOS apps using Apple's innovative programming language, Swift
. . .
* 7-8 months if you can commit 10 hours per week * 3-4 months if you can commit 20 hours per week
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So assuming one spends 40 hours a week (normal work week) in 1.5-2.0 months you will be a 'accredited' iOS developer.
Sorry, I wouldn't hire you, and I can't remember a place I worked at that would.
They will just be like the MCTS or whatever from Microsoft, but without at least a 'governing' body that issues the requirements. Just something to add to your resume to work at a place that doesn't know how to do hiring.