The question of how the atomic nucleus self organizes is central in nuclear structure physics. In this talk, we approach the problem of nuclear clustering with a microscopic Configuration Interaction method. We construct reaction cluster channels in a Harmonic Oscillator many-body basis that respect the symmetries of the Hamiltonian, are fully antisymmetrized, and carry a controlled center of mass contribution. The channels are subsequently used to probe the cluster aspects of various nuclear states obtained through Configuration Interaction Methods. To target the emergence of clustering from first principles, we employ the Resonating Group Method with the microscopic cluster basis within the No Core Shell Model framework. Results for 2α and 3α systems will be presented.