Nya is the palatal nasal and closes the second class. Like the velar nasal before it, it does not begin a Sanskrit word and occurs essentially only before another consonant of its own class, so it is met inside conjuncts far more often than standing alone. The independent letter is largely a chart entry; the cluster is what a reader actually encounters.
The most consequential of those clusters joins it to the voiced palatal and opens the Sanskrit word for knowledge, which is among the most frequently written words in the whole Buddhist vocabulary. Its written form is a single shape, and the way that shape is pronounced differs sharply between regions of India, a divergence that concerns the spoken language rather than the script.
Its position closes the class as the nasal closes each of the other four, and the five nasals taken together, one from each point of articulation, are among the most quoted results of the Indian analysis of speech. No other ancient description of a language separates nasals by place so cleanly, and the arrangement is one of the things that made the table worth studying in East Asia as a piece of linguistics.
Because it is met almost entirely inside clusters, it is one of the letters whose independent form a learner may know only from the chart. That is not a defect in the teaching. The chart is the object being learned, and knowing where a letter stands in it is a different kind of knowledge from being able to pick it out of a word.