"Life couldn't have formed by random chance"

Chemistry is not random chance nor is Biology.

First of all nobody is claiming that life started out complex. In the beginning it was extremely simple. Life started slow and Self-replicators were made, which can be incredibly simple, as simple as a strand of six DNA nucleotides. This is simple enough to form via organic chemistry. Self-replication sets the stage for evolution to begin, whether or not you call these Self-replicators "life."

While evolution via natural selection currently suggests that random mutation in the genome is the source of variation, the driving forces behind selection are decidedly not random. In fact, Natural Selection is the complete opposite of random chance.

The Mount Improbable analogy gives a good explanation of how Evolution creates complexity. Mount Improbable has two sides, one being a gradual slope and the other being a sheer cliff. The peak of this mountain symbolizes complexity or a complex organ, such as the eye. Evolution does not get to complexity by jumping up the cliff wall; it does by walking up a gradual, easy slope, from simplicity to complexity.