G = 6.67 x 10-11 N•m2/kg2
G = 6.67 * 10-11 m3/kg-1s-2
It's great that you are paying careful attention to units, kudos to you!
Let's work the problem testing the mostly likely hypothesis - that they are the same thing, not different. After all, as you likely suspect, there can't really be two different ones.
What happens if we set them equal to each other?
6.67 x 10-11 N•m2/kg2 = 6.67 x 10-11 m3/kg-1s-2
get rid of numerical value:
N•m2/kg2 = m3/kg-1s-2
get rid of "extra" meters:
N/kg2 = m/kg-1s-2
Multiply kg2 on both sides:
N = m•kg/s-2
Hmmm, now what does Wikipedia say a Newton is?
The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s2, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second.
So we're okay, these are the same physical values, one that includes a Newton explicitly as "N", and the other that writes it out "long form" kg⋅m/s2.