Words that start with 'ni' and contain 'n'

What is the highest scoring word in Scrabble you can play for ?
With a vast 319 entries, it's best to opt for 'nijinsky' which scores 22 points.

What's the most popular word on this page?
'Nine' is the most popular word from this that start with 'ni' and include 'n', ranked 1770^th most common word.

How many characters does the largest word from this list consist of?
The longest word that's possible to construct from the combination searched for is 'nitrotrichloromethane', and it contains 21 characters.

What word from this page is the most interesting?
By far the most interesting word in this list is 'nineteen'. According to the dictionary, 'nineteen' is defined as "Nine and ten; eighteen and one more; one less than twenty; as, nineteen months. 1. The number greater than eighteen by a unit; the sum of ten and nine; nineteen units or objects. 2. A symbol for nineteen units, as 19 or xix.".

In total, how many words are available using the combination requested?
One could make 319 words using this combination.