Mechanical forces and biochemical signaling networks play a crucial role in cell behavior in growing tissues. The nonlinear dynamics of tissue growth arises from complex interactions between cells and their surroundings. However, the role of chemomechanical regulation which governs the size, shape, and structure of multicellular tissues remains insufficiently understood. To investigate this, we develop a thermodynamically consistent phase-field model in the Eulerian framework to simulate nonlinear tissue growth in confined geometries. Our formulation integrates both elastic and chemical energies through an energy variational approach. Additionally, we implement an efficient finite difference based multigrid method with a special boundary treatment to incorporate applied forces. We confirm the validity of our phase-field model by demonstrating its convergence to an experimentally supported sharp-interface model. Furthermore, we examine how elastic forces, variations in tumor and host stiffness, and external forces influence the evolution of single and multifocal tumors in confined geometries.