Try

myTable=Table[0,{x,8},{y,8}];
For[population=100,population>0,population--,
  x=RandomInteger[{1,8}];
  y=RandomInteger[{1,8}];
  myTable[[x,y]]=myTable[[x,y]]+1
];
myTable

and the result is

{{2,2,2,1,1,4,1,3},
 {4,1,1,4,1,1,2,2},
 {2,2,2,1,1,1,0,2},
 {4,0,0,1,0,0,2,2},
 {1,1,4,2,1,1,0,0},
 {0,1,1,0,1,2,1,0},
 {2,0,2,1,2,3,2,3},
 {2,2,1,3,3,3,1,2}}

A functional programming approach:

population = 100;
choices = RandomChoice[Range[8*8], population];
cumulative = Tally[choices];
mySparseList = 
  SparseArray[cumulative /. {n_Integer, freq_} :> ({n} -> freq)];
myTable = Partition[Normal[mySparseList], 8]
Total@Total[myTable] == population

Thank you, that fixed it