The M2 chip will feature new 4nm technology from TMSC (Apple's main chip supplier), which means the new chip will likely be more powerful and energy efficient than its predecessor.
The M2 has the same number of CPU cores as the M1, a total of eight CPU cores, of which four are high-performance cores and four are efficient cores, but it will be upgraded in terms of graphics processing power.
The M1 in the current MacBook Air currently has 2 variants with 7 or 8 GPU cores, but the M2 will have 2 new variants for a total of 9 or 10 cores. The increase in the number of cores, coupled with the new technology, will certainly make the new chip muhc better than last year's model.