Yes, a stock dividend would create dilution. In essence so does a cash dividend. It takes money out of the treasury, makes the company worth less.
Many companies choose stock dividends instead of cash dividends. A stock dividend allows the shareholder to “re-invest” their dividend without paying taxes on such. Or, at their choosing, shareholders could choose to sell their dividend shares, paying taxes, and taking the income.
As far as dilution is concerned, it’s a non-issue. In my example your shares would be worth 20% less and you would own 20% more.
What a stock dividend would do is force those holding NSS to buy stock on the open market to pay this dividend. Shares that may not exist.
Imagine for a moment that the SEC forced you to buy ten apples and deliver them by next Monday. Now imagine for a minute that there were only eight apples on the planet.