The gate delay of the gate depends on the digital logic family which it belongs to.
As far as CMOS logic family is cocerned both will have same gate delays.
For other logic families you may refer to "Integrated Electronics" by Millman Halkias.
I agree that the speed depends on the family logic but remember that different gates (e.g. nand & nor) may have different number of transistors thus the speed may be different. plz refer to a book on the internal circuit of gates to see what criteria are involved!