New to gardening.

Last year, I decided to use large hardwood nuggets as mulch. This was on top of spent pine needles. I was wondering if I can rent a chipper to break the large nuggets into smaller peices. The nuggets are approx 3-4 inches long and may 1-2 inches broad. The reason I want to break them down is, they seem to collect fungus(whitish deposits under them) and I guess it may harm my plants. Also, the large nuggets donot look good and look course.

Pls let me know if there is anything I can do tbreak them down into smaller peices/nuggets. I looked in Home depot to see if they have anything(like a chipper) to rent, but they had none.

Thanks in advance,
EG