Nuggets can be found at Macca's but not this one, it's found in a gold field, or is that gold fields!
GZ is not far away, about 300 metres.
The listed coordinates will guide you to an appropriate place where you can see the appropriate word that you must use in the calculation of the final GZ coordinates which are :
S 34 37.ABC
E 138 50.DEF
Count the number of letters in the appropriate word.
A = # of letters minus 3
B = # of letters minus 7
C = A
D = # of letters minus 4
E = D divide by 2
F = A minus C