Yes and no. It depends on what they're identifying.
It's true that a nano will rarely, if ever, fail to identify a cypher. As the other answers have already noted, the difficulty of identifying a cypher is usually 1 or 2, and as stated on page 86:
By using skills and assets, working together, and - perhaps most important - applying effort, a character can decrease a target's difficulty by multiple steps to make it easier... If she can reduce the difficulty of a task to 0, no roll is needed.
Being specialised in numenera (or being trained in it and having a book about numenera, such as the one all nanos start with) is enough to reduce the difficulty of identifying numenera by 2, which makes identifying cypers automatic.
This is almost certainly deliberate. As the book repeatedly says, cyphers are intended to act more like character abilities than inventory items; A cypher you can't identify is a character ability you can't use but which is supposed to be there for game balance reasons, so I very much doubt that Monte Cook intended players to fail at identifying them.
However, not all numenera are cyphers. The other major categories of numenera are Artefacts, Oddities and Discoveries, and they have different rules for setting identification difficulty.
As per page 299, artefacts can be significantly harder to identify than cyphers:
Once the characters find an artefact, identifying it is usually a separate task, also based on Intellect and modified by knowledge of the numenera. The GM sets the difficulty, of the task, but it is usually equal to the level of the artefact.
Since artefacts run the gamut of levels from 1 to 10, it's clear that most of them aren't nearly as easy to identify as cyphers.
Oddities are numenera items that clearly have weird properties, but which have little obvious purpose or function beyond being novel paperweights and doorstops. As such, oddities can't be identified; They either have no hidden property to identify, or that property is so impossible to discover or gameplay-irrelevant that it might as well not exist. (That said, they can still have plot significance, their odd properties can occasionally be utilised by creative players or they might prove to have some highly useful property in some highly unusual circumstance... But all of those options are unusual deviations from the norm.)
Discoveries are the "miscellaneous" category of numenera, as as such, can be anything imaginable that doesn't fit into one of the other categories. They can have any properties or powers imaginable - and the difficulty of identifying discoveries could be anything, as well. Sometimes you'll want it to be automatic ("It's obviously a portal to somewhere") and other times very hard indeed ("If players identify this, they can cure all diseases forever, but they have to keep it out of the wrong hands"). Anything's possible.
So, like I said at the top, identifying numenera is occasionally automatic, but usually not. Of course, this being numerera,
An exception is if the GM decides to use a GM intrusion.