We determined moment tensor solutions for middle and large-size earthquakes that occurred during the period 1990-2013 in the subduction zone, Nicaraguan forearc and Nicaraguan depression, using inversion analysis of teleseismic waveforms. In order to understand tectonic stress state from the subduction zone to the inland crust in Nicaragua, we estimated stress drop for each earthquake using obtained values of seismic moment and half duration of source time function. We found that the thrust faulting is clearly predominant in subduction zone, generating shallow earthquakes with magnitudes up to more than Mw 7, while in the Nicaraguan forearc the faulting type is mixed including thrust and strike-slip faulting, generating intermediate earthquakes with magnitudes between Mw 5.3-6.9. On the other hand, in Nicaraguan depression the strike-slip faulting with left-lateral motion is predominant, generating shallow earthquakes with magnitudes between Mw 5.3-6.1. Then, we examined the relationship between seismic moment and half duration of source time function, and found that the stress drop for each earthquake is nearly constant between 0.1-10 MPa with no dependence on seismic moment. Earthquakes with a depth of 50-100 km show higher stress drop than earthquakes with a depth of 0-50 km. Our results give information for understanding of tectonics in Nicaragua.