Frederik Vandeputte - Switch function Trick

=SWITCH(TRUE();
[Score] >=1 && [Score] <5; "C";
[Score] >= 5 && [Score] < 8; "B";
[Score] >=8 && [Score] <=10; "A";
"Wrong Value"
)

So SWITCH(TRUE();expression1; value1; expression2; value2; expression3; value3; .... ElseValue)  is the trick for rewriting nested IFs in DAX.

Frederik Vandeputte