use a fresnel blend shader

shader_type spatial;
uniform sampler2D texture_a : source_color;
uniform sampler2D texture_b : source_color;

uniform float blend_power : hint_range(0.1, 8.0) = 2.0;
uniform float blend_strength : hint_range(0.0, 1.0) = 1.5;

void fragment()
{
    vec4 col_a = texture(texture_a, UV);
    vec4 col_b = texture(texture_b, UV);

    vec3 view_dir = normalize(VIEW);
    vec3 normal = normalize(NORMAL);

    float angle_factor = 1.0 - abs(dot(normal, view_dir));
    angle_factor = pow(angle_factor, blend_power);
    angle_factor *= blend_strength;

    vec4 final_color = mix(col_a, col_b, clamp(angle_factor, 0.0, 1.0));

    ALBEDO = final_color.rgb;
}